Do you have a cite for this?

The PDF you link (downstream) does not include a definition.

The DF-160 form lists a set of social networks, not otherwise accessable that I've found, here:

https://ceac.state.gov/GenNIV/General/complete/complete_cont...

Included are: Ask.fm, Douban, Flikr, Google+, Facebook, Instagram, LinkedIn, MySpace, Pinterest, Qzone (QQ), Redit, Sina Waibo, Tencent Weibo, Tumblr, Twitter, Twoo, Vine, Vkontakte (VK), Youko, YouTube, and "none".

Hacker News is conspicuously missing.

What the US government really wants is all your public online accounts.

They used the broad and not fully defined definition of the word to their advantage.

What a social media site is, is something I think we are all collectively defining. It's too new to be really set in stone.

Also, even though words have broad meanings, it doesn't make it right to use it that way, since social customs would make the person using such definitions unintelligible. For example, if I said in my introduction at a party to a woman "I'm gay", she will likely take it to mean 'I'm homosexual', not 'I'm happy'. Both are completely valid dictionary uses. Only one has a valid use in any modern context.

Social media is generally defined as media where the primary intent is socializing. For me, that means it is more about communicating with friends and family in a manner that is directed to furthering my understanding of them, and their understanding of me. These sites would be like facebook, twitter, instagram, etc

Sites like HN, webmasterworld, blackhatworld, etc... are more about advancing knowlledge in a specific area. Socializing is a secondary consequence. These could be considered 'quasi' social media accounts.

Based on the current definition of social media, even comments on a news site or blog, 'could' qualify. But then again we run into the issue that if you use words in non-standard ways you can become unintelligible to your fellow humans, undermining the whole purpose and concept of language. If I said 'I read a comment on social media' and really meant 'I read a comment on cnn.com' people would not understand what I'm saying. It would be odd and awkward.

It's not the same as following in the traditional "use the follow to populate a timeline or feed" sense. I don't come to HN wondering "what did my peeps comment today?", rather I come to glance at particular stories, and perhaps read the comments.

The "engagement" aspect of HN is in the quality of items that make it to the front page, and in the comments. It's not in the slow drip-drip-drip of near-real-time notification regarding the activities of specific users.

The main difference between a 'social media' forum and a topical forum is that in a topical forum there's some expectation of staying more or less, you know, on topic. There is some functional overlap, but more limited domain.

HN is “social”. It’s just not so “social” that I want to throw my router off the balcony upon reading it.